Cleaning machines of the type wherein a washing liquid is fed from a receptacle to a surface to be washed and then, by means of suction, is returned to the original receptacle for further use, preferably after being filtered are known. For example, in Keefer U.S. Pat. No. 1,661,480, such a cleaning machine is disclosed wherein a tank-like receptacle is provided that houses the pump for dispensing the cleaning liquid, the suction fan for returning the liquid, and the filtering means, while also providing the storage facility for the cleaning liquid. The tank-like receptacle is designed to sit on the floor and flexible liquid discharge and liquid return hoses connect the tank-like receptacle with a cleaning head used to apply and retrieve the cleaning liquid from the surface being cleaned.
In Danielson et al U.S. Pat. No. 2,680,260, a form of cleaning machine is disclosed wherein a cleaning fluid is applied by the machine and is recollected through a filter back to a storage tank for recirculation. In the arrangement shown by of this patent, instead of a hose-connected cleaning head being utilized, as in the case of the Keefer patented unit, the underside of a wheeled tank-like receptacle (which houses the storage tank, pump and the like) has a cleaning liquid supplying conduit arranged to supply fluid centrally through a rotating brush that scrubs the surface to be cleaned. A circular mouthpiece surrounds the periphery of the brush and collects the liquid for return back up into the tank.
While devices of the aforementioned type are portable, they are anything but compact and lightweight, particularly when their cleaning fluid tank is full. Furthermore, the presence in such apparatus of a tank that must rest on the floor not only makes use of the apparatus cumbersome, but is restrictive with respect to the places that such a unit can be effectively utilized. For example, long flights of steps having no landing upon which the tank can rest can render the apparatus unusable. Furthermore, because of the cumbersome nature of such units, it is often impractical to utilize the unit for spot cleaning purposes, such as cleaning up a small spill, as opposed to general room cleaning.
As a result, it is desirable to have a cleaning apparatus wherein all of the operative components are mounted upon a common element so that the unit is unencumbered by a separate floor-supported tank. Lynch, Jr. U.S. Pat. No. 4,156,952, and Krammes U.S. Pat. Nos. 3,040,362 and `,986,764 show floor cleaning apparatus, configured similarly to an upright vacuum cleaner or so-called electric broom, that have all of the operative components for spraying a cleaning fluid onto a floor surface, such as a carpet, and for using suction to collect the dirty cleaning liquid, such as a means for storing the fluid that is applied and collected, mounted upon a common element. However, the versatility of such "common element" type cleaning apparatus is severely restricted to floor-type uses, because these units are too large and heavy to be used in a manner that is unsupported by contact with the floor surface to be cleaned and because the units are not designed for operation in orientations that would be necessary for cleaning vertical or inclined surfaces. Also, these units, while more compact and lightweight than the initially mentioned tank-type units, are not truly lightweight or compact either.
Attempts have been made to provide light weight, hand held cleaning units, but such units have not been capable of handling substantial amounts of cleaning fluid. Instead, these units are essentially vacuum cleaners which may be adapted to handle a limited amount of fluid present on a surface to be cleaned. They are not provided with cleaning fluid supply systems nor are they designed to exclude fluid from the operating portions of the unit. U.S. Pat. No. 4,536,914 to M. M. Levine illustrates a wet-dry vacuum cleaner of this type.